In our copending application, now U.S. Pat. No. 4,289,630, there is disclosed a pressure filter which incorporates a vibratory impactor for imparting vertical shock waves to a rigid outlet manifold from which a plurality of filter elements are suspended. In that filter the manifold is mounted to the tank by resilient members such as rubber bumper springs or by mechanical springs wherefor the vibrational waves are transmitted directly to the filter elements and are not appreciably dampened by the massive tank.
One type of filter element which finds use with the above described pressure filter is described in U.S. Pat. No. 3,695,443, assigned to the same assignee as is the present invention. That type of filter element is tubular in construction and has a fine mesh sleeve formed of woven cloth or the like which fits over a rigid, tubular core member. In those applications where the length-to-diameter ratio of the filter element is more than about eight-to-one, less than perfect cleaning may occur due to relative movement between the core member and the filter sleeve and a consequent low efficient wave transmission to the sleeve. It would be desirable, therefor, to improve the transmission of the vibratory shock waves from the core member to the entire filter sleeve in relatively long filter tubes.
Another problem which is sometimes encountered with relatively long filter tubes is the tendency for the tubes to bow and thus adversely affect the transmission of vibrational shock waves from the cores to those areas of the mesh sleeves where the sleeves become spaced from the cores. It would, therefore, be desirable to provide a filter tube having greater physical strength to resist bowing without appreciably increasing the weight of the tube or adversely affecting its operating characteristics.